"Quan" was last seen riding his mountain bike, which is spray-painted gold, in the area of King Avenue and Chester Pike around 3 p.m. Monday. He had on a blue and white collared shirt, blue jeans and black sneakers and carried a gray backpack when he went missing, said the FBI.

They say the case is considered suspicious and Quan doesn't have a phone on him.

"He did leave his cellphone at his house," said FBI spokesman JJ Klaver. "... he's never run away before, he's never gone missing before... there's no clear indication of foul play at this point but we are considering every possibility," said FBI spokesman JJ Klaver.